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  <div class="section" id="module-whichdb">
<h1>12.7. <tt class="xref docutils literal"><span class="pre">whichdb</span></tt> &#8212; Guess which DBM module created a database<a class="headerlink" href="#module-whichdb" title="Permalink to this headline">¶</a></h1>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">The <tt class="xref docutils literal"><span class="pre">whichdb</span></tt> module&#8217;s only function has been put into the <a title="(Unix) The standard &quot;database&quot; interface, based on ndbm." class="reference external" href="dbm.html#module-dbm"><tt class="xref docutils literal"><span class="pre">dbm</span></tt></a>
module in Python 3.0.  The <a class="reference external" href="../glossary.html#term-to3"><em class="xref">2to3</em></a> tool will automatically adapt imports
when converting your sources to 3.0.</p>
</div>
<p>The single function in this module attempts to guess which of the several simple
database modules available&#8211;<a title="(Unix) The standard &quot;database&quot; interface, based on ndbm." class="reference external" href="dbm.html#module-dbm"><tt class="xref docutils literal"><span class="pre">dbm</span></tt></a>, <a title="(Unix) GNU's reinterpretation of dbm." class="reference external" href="gdbm.html#module-gdbm"><tt class="xref docutils literal"><span class="pre">gdbm</span></tt></a>, or <a title="DBM-style interface to the BSD database library." class="reference external" href="dbhash.html#module-dbhash"><tt class="xref docutils literal"><span class="pre">dbhash</span></tt></a>&#8211;should be used to open a given file.</p>
<dl class="function">
<dt id="whichdb.whichdb">
<tt class="descclassname">whichdb.</tt><tt class="descname">whichdb</tt><big>(</big><em>filename</em><big>)</big><a class="headerlink" href="#whichdb.whichdb" title="Permalink to this definition">¶</a></dt>
<dd>Returns one of the following values: <tt class="xref docutils literal"><span class="pre">None</span></tt> if the file can&#8217;t be opened
because it&#8217;s unreadable or doesn&#8217;t exist; the empty string (<tt class="docutils literal"><span class="pre">''</span></tt>) if the
file&#8217;s format can&#8217;t be guessed; or a string containing the required module name,
such as <tt class="docutils literal"><span class="pre">'dbm'</span></tt> or <tt class="docutils literal"><span class="pre">'gdbm'</span></tt>.</dd></dl>

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